Abstract: Objective: To optimize the extraction technology and study the antioxidant activity of total flavonoids from the Kadsura coccinea flowers. Methods: The optimum extraction process of total flavonoids from the Kadsura coccinea flowers was optimized by single factor test (ethanol concentration, ultrasonic time, solid-liquid ratio, ultrasonic temperature) and orthogonal experiment. The scavenging ability of total flavonoids on ABTS and DPPH free radicals was evaluated. Results: Full opening period(June), ultrasonic time 45 min, solid-liquid ratio 1:30 mg/mL, ultrasonic temperature 60 ℃, ethanol concentration 85% were the optimal extraction conditions, the extraction quantity of optimum extraction condition was 19.25 mg/g. When the concentration of total flavonoids was 0.8 mg/mL, the scavenging rate on DPPH free radical was 82.1%, it was 87.9% of that of vitamin C. When the concentration of total flavonoids was 0.4 m, the scavenging ability on ABTS free radical was similar to that of vitamin C. The IC₅₀ of total flavonoids from the Kadsura coccinea flowers against DPPH free radical and ABTS radical were 0.13, 0.046 mg/mL, respectively.Conclusion: The extraction method is feasible and the extraction conditions are reliable, the total flavonoids of Kadsura coccinea flowers can be used as a source of natural antioxidants.